Open Access
Table I.1
Description of the columns of the provided catalog.
| Name | Description | Units |
|---|---|---|
| ls_id | Unique object identifier in the Legacy Surveys or DECaLS database. | N/A |
| ra | Right ascension (ICRS/J2000 as provided by the survey catalog). | degrees |
| dec | Declination (ICRS/J2000 as provided by the survey catalog). | degrees |
| a | Object semi-major axis (from detection). | Pixels |
| b | Object semi-minor axis (from detection). | Pixels |
| theta | Object position angle (from +x to major axis). | Radians |
| npix | Number of pixels in the detection segmentation mask. | N/A |
| rp | Petrosian radius computed with an elliptical aperture. | arcsec |
| r50 | Radius containing 50% of the flux computed with an elliptical aperture. | arcsec |
| rkron | Kron radius. | arcsec |
| maingalaxy_flag | 1 if no object is detected at the image center (e.g., center pixel label ≤ 0). | 0 or 1 |
| rflag_pixels | Radius of the circular aperture used in flagging and neighbor checks (1.5 Rp). | Pixels |
| edge_flag | 1 if there are zero or NaN-valued pixels within the flagging area. | 0 or 1 |
| N_rcheck | Number of secondary objects within the flagging area. | N/A |
| Nsec_flag | 1 if there are more than 4 objects within the flagging area. | 0 or 1 |
| N_deltaMAG | Number of secondary objects with magnitude difference smaller than 1. | N/A |
| minMAG_diff | Magnitude difference to the brightest secondary object. | N/A |
| dist_minMAG_diff | Distance to the brightest secondary object. | Pixels |
| BrightObj_flag | 1 if there is a bright object within the flagging radius (as defined in the pipeline). | 0 or 1 |
| normDist_closest | Distance to the closest secondary object, normalized by Rp. | N/A |
| mup | Average pixel value at 1Rp (surface-brightness proxy at the Petrosian scale). | Image units |
| C | Concentration index (e.g., based on r80 and r20). | N/A |
| r20 | Radius containing 20% of the flux (elliptical aperture). | Pixels |
| r80 | Radius containing 80% of the flux (elliptical aperture). | Pixels |
| A | Asymmetry index. | N/A |
| Ashape | Shape asymmetry index (“A3” in the warning bitmask). | N/A |
| S | Smoothness index. | N/A |
| M20 | M20 index. | N/A |
| xc_M20 | Pixel x coordinate that minimizes the total second-order moment. | Pixel |
| yc_M20 | Pixel y coordinate that minimizes the total second-order moment. | Pixel |
| E | Shannon entropy index. | N/A |
| Gini | Gini index. | N/A |
| G2 | Gradient pattern asymmetry index (GPA). | N/A |
| pspiral | LightGBM probability that the galaxy is spiral (only available for the 1.7 million catalog). | N/A |
| status | Processing status: 0 = full success; 1 = not success (failed); 2 = success with warnings. | 0, 1 or 2 |
| warn_mask | Warning bitmask (decoded in Table I.2). | see Table I.2 |
| err_code | Error code explaining why processing failed (decoded in Table I.3). | see Table I.3 |
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